The photo exploded the moment it hit the internet: Eight white high school girls, each wearing a white shirt, grin for the camera as some raise their hands to form triangles above their heads. The right side of the frame holds three letters: KKK.

"(This) is white girls at Barrington High School everyone, always setting great examples!" reads the tweet that appears to have brought the photo to public attention Monday.

By the next day, Barrington District 220 was under siege from people who believed the gesture was meant to simulate Ku Klux Klan hoods, and who demanded school officials take action against the students.

That was followed by a small protest at the school Friday morning, where students from Barrington and other area schools gathered to express their grievances.

"I'm pretty upset," said incoming Barrington senior Mia Fields. "People at our school are very prejudiced."

Superintendent Brian Harris issued a statement Thursday saying the district "does not condone the actions of the students in the photo and the matter is under investigation. Once the investigation is complete, we will determine the appropriate consequences, according to our student handbook and board policy."

But in an interview Friday, he said he didn't know if the photo indicated any wrongdoing.

Jim Young / Chicago Tribune

Brian Barnes puts his arm around his daughter Mia Fields as they listen to principal Steve McWilliams during a protest outside Barrington High School on July 14, 2017.

Brian Barnes puts his arm around his daughter Mia Fields as they listen to principal Steve McWilliams during a protest outside Barrington High School on July 14, 2017.

(Jim Young / Chicago Tribune)

The meaning of the girls' gesture is ambiguous — the Southern Poverty Law Center, which tracks hate groups, told the Tribune it doesn't match any known Klan hand signs — and a text message pinging around social media claims that "KKK" are the initials of one of the girls pictured.

Ryan Lenz, a spokesman for the center, said while so-called alt-right groups have begun to imbue formerly inoffensive objects and gestures with racist meanings — the "OK" symbol is one example — he saw nothing alarming in the image posted by the Barrington students.

"My first impression on looking at the photo would not be that these girls are doing something racist," he said.

Harris said that because the school is on summer hiatus, district officials haven't been able to speak with everyone in the photo to clear up the matter.

"It's been challenging to try to gather information on what actually occurred and what didn't," he said.

The Tribune reached out to the families of the girls allegedly pictured in the photo. None responded.

Chicago attorney Matt Cohen, who represents students in school disciplinary cases, said administrators are increasingly trying to govern off-campus internet use if they believe it interferes with school operations.

Barrington's student code of conduct contains that provision, saying off-campus computer use that creates "material and/or substantial disruption to the school environment" could be a disciplinary matter.

Cohen said such broad language puts too much power in the hands of administrators.

"My personal opinion is that that's a gross overreach on the part of schools," he said. "There are both free speech issues and a privacy issue, and the issue of potentially extending school discipline far beyond what's necessary to govern school."

The tumult over the photo has played out mostly in cyberspace, with images hurling around Twitter and Facebook that show not only the gesture, but also text messages purportedly written by some of the participants — messages that contain flippant and racially inflammatory language.

The images have been retweeted and shared thousands of times, generating furious replies. Harris said school officials were initially concerned for the girls' safety, though Barrington police said Friday they were not aware of any threats.

Denise Rodriguez, a 2016 graduate of the school, called for others to leave a blizzard of 1-star reviews on the district's page as an act of resistance, but that sparked a counterstrike of 5-star reviews. The back-and-forth left the district's Facebook rating at 3.9 stars as of Friday afternoon.

Rodriguez said she took offense to the image at first sight. She said it was clearly an attempt to mime Klan hoods, and that it was resonant of other racial slights she felt during her time at the school, which is 68 percent white, 16 percent Hispanic, 11 percent Asian, 3 percent multiracial and 2 percent black.

She said some white students appropriated cultural symbols in a disrespectful way, from wearing stereotypical Mexican and American Indian garb at powder puff football games to mimicking "gangsta" wear in the hallways. School officials rarely restrained them, she said.

"Many people of color were completely upset about this," she said. "I think there has been racial tension throughout my time at this district."

Harris disputed the idea that widespread racial unrest exists at the school, other than "isolated incidents where kids make poor choices. … That's part of our duty, to navigate that. We embrace diversity."

Some upset by the photo called for a protest at the high school Friday, and when the time arrived, seven showed up. They were swiftly met by two administrators in the cavernous, almost-empty parking lot, and the would-be rally became more of a quiet discussion.

Principal Stephen McWilliams said the image "burns me to my core," and he encouraged the students to forward other posts they found offensive. He said they had been "good citizens" to raise the issue.

Fields' father, Brian Barnes, stood nearby listening to the discussion. He said he had not agreed with the way "similar situations" had been handled at the school, but hoped this one would be ironed out.

"I was telling my daughter hopefully this is a misunderstanding, like a pic for a meme," he said. "Still, she's pretty much shocked."

John Keilman is a Tribune reporter; Todd Shields is a Pioneer reporter.